Small form-factor keyboard using keys with offset peaks and pitch variations

ABSTRACT

A small form-factor keyboard or keypad for key structures is provided in which individual key structures have a contact surface on which there is a center reference and a peak. The center reference and the peak or offset, so that an offset distance between the center reference and the peak is greater than or equal to zero. The offset distance for at least two or more key structures in the plurality of key structures may different. The difference in the offset distance may be based on a position of the individual key structures relative to a first reference line.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/144,098, filed Jun. 2, 2005 entitled SMALL FORM-FACTOR KEYBOARD USINGKEYS WITH OFFSET PEAKS AND PITCH VARIATIONS; the aforementioned priorityapplication being hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The disclosed embodiments relate generally to the field of keyboards formobile computing devices. In particular, the disclosed embodimentsrelate to a small form factor keyboard having offset pitch and peakvariations.

BACKGROUND

Over the last several years, the growth of cell phones and messagingdevices has increased the need for keypads that are small and tightlyspaced. In particular, QWERTY keypads have become smaller with greaterkey switch density. With decreasing overall size, there has been greaterfocus on efforts to make individual keys more usable to a user. Forexample, keyboard design considers how readily the user can select orclick (“clickability”) individual key structures of keyboard. Theclickability may be affected by various factors, such as the individualkey structure size and shape, as well as the spacing between keystructures and the tactile response of individual key structures.

With the growth of small form factor devices, such as cell phones andwireless messages, there have been several designs and schemes forproviding smaller functional keypads, particularly with respect tokeypads that provide character entry. For example, keyboard layouts havebeen designed using button structures and individual key orientationsthat reduce the overall surface area of the keypad. Such designs haveoften focused on QWERTY keyboard layouts, which normally require atleast 26-30 individual keys.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates key set design, under an embodiment of the invention.

FIG. 2 is an illustrative cross-sectional view along lines A-A of FIG.1, illustrating the shape of each key in a given column along a givenaxis.

FIG. 3 is an illustrative cross-sectional view along lines B-B of FIG.1, illustrating the shape of each key in a given portion of a row alonganother axis.

FIG. 4 illustrates a mobile computing device having a keyboard providedunder an embodiment of the invention.

FIG. 5 illustrates a mobile computing device with a keyboard designimplemented under an embodiment of the invention.

DETAILED DESCRIPTION

Embodiments of the invention provide a small form-factor keypad orkeyboard that utilizes its exterior contour and shape to enhanceusability. According to an embodiment, a keyboard is provided havingindividual key structures that have offset peaks and/or pitchvariations. The offset peaks and/or pitch variations provide tactileseparation of individual keys, so that the keys feel further apart tothe user as compared to keys that are uniformly shaped. In a small formfactor keyboard, the user can better distinguish individual buttons orkeys because the keys or buttons are more distinguishable to touch.Additionally, the space needed to provide a full set of keys (e.g. asrequired in a QWERTY layout) may be reduced, without sacrificing theuser's ability to effectively identify and select individual keystructures using thumbs or finger tips.

While there have been past attempts to facilitate touch or thumb typingon small form keypads, many of the past approaches have focused on keyorientation (e.g. angled keys) and key spacing. In contrast to pastapproaches, embodiments of the invention provide for key structures thatare contoured to have peaks or other outward formations. Withinindividual keys, the peaks may be spaced from the center point.According to embodiments described herein, the spacing between the peakand center points is varied from key to key, so as to provide the userwith tactile separation. In order to achieve the tactile separation, therelative position of the peak with respect to the key's center point isbased on the position of that key in the key set or keyboard. In oneembodiment, the peak-to-peak separation between adjacent keys of akeyboard is uniform and greater than a center-to-center separationbetween the same keys.

Overview

According to one embodiment, individual keys in a key set or structuredso that the surface of each key includes a pitch or other surfacevariation that forms a raised-strike point (alternatively referred to asa peak) for that key. The raised strike point may be made offset fromthe center point or centerline of some of the individual keys. In anyparticular key, the existence and degree of offset between the strikepoint and the center point may be based on the relative position of thatkey in the key set or keyboard. In one embodiment, a relative positionof the raised strike point of individual keys may be gradually shiftedin one direction and/or another from key to key, so that so that thespacing between an interior center reference of adjacent or neighboringkeys (such as center point to center point) may be made less than thespacing between the raised strike points of the same respective keys.The larger spacing between shifted strike points of adjacent keysprovide tactile separation for the user.

Embodiments of the invention may be implemented in the context of akeyboard or keyboard device. One embodiment includes a QWERTY layout forkeys of a keyboard, with individual keys in the keyboard being providedan exposed surface on which a strike point and pitch are provided. Thepitch and strike point position may vary slightly from key to key, withvariations being most pronounced on edge keys (those keys that arefurthest from a centerline of the keyboard). This provides greaterspacing between strike-points for all keys of the keyboard.

An embodiment includes a keyboard having a plurality of key structures.The key structures that form the keyboard may be distributed in adirection of at least a first axis. Each key structure in the pluralityof key structures may include an exterior surface for receivinguser-contact. The exterior surface of each key structure may include acenter reference and a peak, so that an offset distance between thecenter reference and the peak is greater than or equal to zero. Theoffset distance for at least two or more key structures in the pluralityof key structures is different. The difference in the offset distancemay be based on a position of the individual key structures relative toa first reference line.

In an embodiment, a magnitude of the offset distance in the direction ofthe first axis ranges from (i) a minimum for one or more key structurethat are closest to the first reference line, to (ii) a maximum for oneor more key structures that are furthest to the first reference line.Additionally, a peak-to-peak distance between the peaks of keystructures that are adjacent in the direction of the first axis is aboutequal for key structures in at least a majority of the plurality of keystructures.

Throughout this application, numerous references are made tomeasurements, such as distances and positions. The use of language, suchas “substantially”, “about” or “approximately”, in the context ofdefining or quantifying such measurements are provided to give somemargin of variation as deemed practical given the context of the usage.For example, two quantities may be deemed about equal to each other ifthey are within 5% of one another.

In one embodiment, the center reference of a key structure may include aline, point, region or other area on an exterior surface (the surfacethat is to be in contact with the finger tip or other key strikingelement) that is central to the boundary of that key structure. In thecase where the keyboard include asymmetrical shaped keys, or keys ofvarying shapes, the center reference may correspond to any convenientinterior reference for providing a consistent measurement of theseparation between keys, so as to provide a comparison for theseparation provided by shifting and/or offset peaks.

The peak of a key structure includes a line, point, region or other areaon an exterior surface having the greatest height, as measured from theunderlying surface used for the key structure.

Keyboard Layout

FIG. 1 illustrates key set design, under an embodiment of the invention.In particular, a key set 100 is arranged to provide individual keys 102corresponding to alphanumeric characters. Other input functions may alsobe provided through use of the individual keys. According to oneembodiment, each key 102 in the key set is a structure, such as apressable button or a deformable member. In a typical scenario, thepressing of each such structure may cause actuation of an electricalsignal that is then identified by internal resources of a hostelectronic device as a character entry, or some other form of input.

The key set 100 may be provided on any one of a plurality of devices ormediums. In one embodiment, the key set 100 is provided on an electronicdevice having a form factor that enables the device to be readilycarried with one hand, or placed in a pocket. Examples of devices withsuch form factors include personal digital assistances (PDAs) such asPALM TUNGSTEN models manufactured by PALMONE, INC., the BLACKBERRYmodels manufactured by RESEARCH IN MOTION, and the IPAQ modelsmanufactured by HEWLETT-PACKARD INC. Other examples of such small formfactor devices include cellular phones and devices capable of messagingacross wireless or cellular data lines, including for example, theHANDSPRING TREO models. An embodiment of the invention may beimplemented on attachment or accessory device for a PDA or cellularphone. For example, a keyboard layout such as described with FIG. 1 maybe implemented on an attachable and detachable keyboard device for PDAsand cellular phones. Such attachment devices may be equipped withconnectors or other connectivity means to transfer data corresponding tokey selections to a processor of the electronic device. In still anotherimplementation, an arrangement such as shown and described with FIG. 1may be provided with a larger form-factor device, such as a laptopcomputer.

As will be described, an embodiment such as illustrated by FIG. 1 may beimplemented to promote the use of thumb-typing. In particular,thumb-typing is made easier in that the user can more readilydistinguish keys through sensation of his or her thumbs. Thumb-typinggenerally refers to the practice of typing with the primary use of oneor two thumbs, usually on a small form-factor keyboard. For example, onetypical thumb-typing technique is to hold an electronic device with twohands, then move one or both thumbs to select individual keys on thekeyboard, as needed. In many cases, the user's thumb covers several keysat one time. In these cases, uniform shaped keys are hard to distinguishthrough touch. Furthermore, in order to select a desired key (once it isdistinguished), the user may angle his thumb to reduce the surface areaon the keys so as to more precisely make the desired selection. Whenrepeated over time, thumb-typing in such cases can be tedious to theuser. The design of spaced strike points, as described by embodiments ofthe invention, enable thumb-typing users to more readily distinguish onekey over another key using touch (such as from the surface of a thumb).Furthermore, because the spaced-apart strike points make the individualkeys more distinguishable, the user can select or press a desired keymore easily, so as to require less focus on angling or directing histhumb surface to the selected key.

In FIG. 1, the keys 102 of the key set 100 are distributed abouthorizontal and vertical reference lines (X and Y). The particulararrangement presented is for a QWERTY style keyboard, althoughembodiments of the invention are equally applicable to other types ofkeys set arrangements, such as, for example, DVORAK or number padlayouts. As such, the key set 100 includes three rows and ten columns.

Individual keys 102 of the key set may include a center point 110 and astrike point 112. The center point 110 and the strike point 112 of eachkey may correspond to a respective region or surface area on an exposedsurface of the key 102. The strike point 112 of any particular keyrefers to a peak, meaning a raised area that is more likely to be struckwhen the user presses or otherwise makes contact with the key 102. Thecenter point 110 is just one example of a reference point (particularlywhen symmetrically shaped keys are used), and other reference points(such as an edge point or on off-key location) or locations may besubstituted in providing this description. However, the use of centerpoints 110 provides a basis for comparison with previous keypadstructures that aligned strike points with the center points. Forsimplicity, symmetrical and identical keys 102 are assumed, so that thecenter point 110 is similarly situated on each key. Furthermore, in FIG.1, each key 102 is assumed to be spaced equally apart. The result isthat a horizontal reference point distance 130 (in the direction X)between the center points 110 of adjacent keys 102 are the same.Likewise, a vertical reference point distance 132 (in the direction Y)between the center points 110 of adjacent keys 102 are also the same. Inan embodiment shown, the equidistance relationships between centerpoints of keys 102 in both the X and Y directions holds true across apertinent span (e.g. the 26 keys assigned alphabetical characters) ofthe key set 100. The assumptions used in describing an embodiment ofFIG. 1 may be changed or ignored with other embodiments andimplementations, depending on particular design implementations as thecase may be.

While the horizontal and vertical center point distances 130, 132 areassumed to be the same between any two pair of adjacent keys when thehorizontal or vertical directions are considered, the position of thestrike points 112 relative to the center point 110 of any particular key102 varies amongst keys spanning in the X and Y directions respectively.In one embodiment, the position of the strike point 112 on each key 102is inversely affected by the position of the corresponding key from acenterline or reference line of the key set 100 as a whole. In anexample shown, centrally located keys in row 143 and columns 151, 153have near or complete overlap between the strike points 112 and thecenter points 110. A distance 118 measured between the strike point 112and the center point 110 is minimal, zero or almost zero. For the keys102 in rows 141 and 145 (above and below row 143) and columns 151 and153, the strike points 112 are off center along the axis Y. In row 141,the strike point 112 is above center point 110, so that distance 118 hasa positive magnitude in the Y direction. In row 145, the strike point112 is below the center point 110, so that the distance 118 has anegative magnitude in the Y direction. A vertical peak-to-peak distance142 is thus constant between adjacent pairs of keys 102 in both ofcolumns 151, 153. This vertical peak-to-peak distance 142 is greaterthan the vertical reference distance 132, as measured between centerpoints 110 of the same pairs of keys 102.

Moving rightward from the axis Y, the position of the strike points 112migrates off-center positively along the axis X. The keys 102 in edgecolumn 159 have the greatest distance 118 between the center point 110and the strike point 112. The key in row 143 of column 147 may beoff-center in only the X direction, the key in row 141 of column 159 isoff-center positively (above row 143) in the Y direction, and the key inrow 145 of column 159 is off-center negatively (below row 143) in the Ydirection. A horizontal peak-to-peak distance 140 between the strikepoints 112 of adjacent keys 102 along the axis X may be equidistant.Furthermore, an embodiment provides that the horizontal peak-to-peakdistance 140 between the strike points 112 of the adjacent keys 102 maybe greater than the horizontal reference distance 130 between the centerpoints 110 of adjacent keys 102 in the X direction. Thus, for example,the magnitude of the distance 118 between the center point 110 and thereference point 112 of the corner keys in column 159 are a maximum, asthey include a maximum component in each of the X and Y directions. Themagnitude of the distance 118 between the center point 110 and thereference point 112 of the key 102 in the center row 143 of column 159has a maximum component only in the X direction.

In an embodiment such as described in FIG. 1 provides for key set 100 tobe symmetrical about the axis Y. This, the strike points 112 may migrateleftward as the key spans negatively along the axis X. The corner keys102 of the left edge column 149 may include the strike points 112 thatare positioned in far left top and bottom corners, so that the distance118 of those respective keys is about the same as the right column 159keys.

While an embodiment illustrated with FIG. 1 includes square shaped keysurfaces, other embodiments may use other shapes, such as circular orelliptical. Individual keys may also be irregular or non-symmetrical inshape. In such cases, the distance measurement may correspond to acommon (on-key or off) reference point and the strike point of therespective key. For example, the distance between the strike point andany on-key reference point may increase for keys that are further fromthe centerlines and/or nearer to the edges of the key set.

FIG. 2 is an illustrative cross-sectional view along lines A-A of FIG.1, illustrating the shape of each key in a given column along the axisY. As illustrated, each key 102 may correspond to a structure 210 thatcan be pressed, moved inward, or otherwise actuated with touch orcontact. In one implementation, the structures 210 are interconnected bya medium 215. For example, medium 215 may be formed from flexiblematerial, such as plastic or flexible injection-molded materials. Thestructures 210 and the medium 215 may be formed from a common material.In this respect, the key set 100 may be an integrated or unitarystructure. Each structure 210 may extend a thickness t from the medium215 to form an exposed surface 220 having a peak 222. The exposedsurface 220 may form the contact surface for the user. The peak 222 maycorrespond to the strike point 112 of FIG. 1. The peak 222 may be formedby shaping the exposed surface 220 to rise and fall at a particularlocation.

Each structure 210 may form a pitch 212, illustrated by a reference lineC (rise to peak and run to position of peak along axis Y). The pitch 212in FIG. 2 is measured between an edge reference 214 and the peak 222,although other reference points may be used. The pitch 212 of eachstructure 210 may vary in the Y direction. If each peak 222 is of thesame height, the variation in pitch 212 amongst different keys may beattributed to the migration of the peak 222 along the axis Y from key tokey.

In the example provided by FIG. 2, the left-most structure 210 (whichmay correspond to any key 102 in the first row 141 of FIG. 1) may beprovided with a peak 222 that is positioned leftward with respect to acenter point 208. The resulting pitch 212 is oriented towards the leftside of the center point 208. When the adjacent key structure 210 isconsidered, the peak 222 may migrate right-ward (which corresponds todownward direction in FIG. 1), so that in the middle structure 210(corresponding to the key 102 in the center row 143 of FIG. 1), the peak222 is aligned substantially with the center point 208. In the next key,the peak 222 is to the right of the center point 208, symmetricallydisposed with the left key 102.

As shown by FIG. 2, the pitch 212 from key structure 210 to keystructure may actually vary as a result of the position of the peak 222changing. The position of the peak 222 may change about any referenceline or point. For example, in FIG. 2, the peaks 222 are symmetricallydisposed about a horizontal centerline.

As described in FIG. 1, a distance 228 may correspond to the distancebetween the peaks 222 of adjacent key structures 210. This distance maybe larger than a vertical reference distance 238 between center points208 of adjacent keys, or the distance 248 between edge points ofadjacent keys. According to some past approaches, when symmetrical keyshapes are used without offsetting peaks 212, the strike point of eachindividual key structure may be approximated as the center point of thatstructure. The distance between center points would then determine theuser's ability to distinguish one key from another. In contrast to suchapproaches, the distance 228 of adjacent peaks 222 is larger than thevertical reference distance 238 that separates adjacent center points208 in the Y-direction. This provides the user with the sensation thatthere is more room between the adjacent key structures, as theindividual key structures are more distinguishable through touch.

FIG. 3 is an illustrative cross-sectional view along lines B-B of FIG.1, illustrating the shape of each key in a given portion of a row alongthe axis X. In FIG. 3, half of first row 141 is illustrated, beginningwith column 153 and extending to column 159. When viewed along the axisX, the individual key structures 210 are more narrow in dimension 211,meaning the footprint for each structure 210 is smaller and more curvedthan when the same structure 210 is viewed along the axis Y.

In the reference frame of FIG. 3, the peak 222 of the structure 210 incolumn 153 is centered, at least when compared to the other keystructures 210 in the same row. The structure 210 in the next column 155may have its peak 222 slightly shifted away from its center point 208.This migration may be repeated, so that in column 159, the peak 222 ofthe structure 220 is at its furthest position from the center point 208along the axis X.

As with an embodiment described in FIG. 2, a horizontal peak-to-peakdistance 268 may be greater than the distance between the center points208 of each adjacent key structure 210. By providing the peaks 222 to beseparated by the distance 268, rather than for example the horizontalreference distance 258 (measured between adjacent center points alongaxis X), adjacent keys can be more readily sensed and distinguishedthrough touch when the key set 100 is in use.

When FIG. 2 and FIG. 3 are viewed together, the peaks 222 of individualkey structures 210 can be understood as having a two-dimensionalvariance from key to adjacent key. This variance may be expressed as avector formed by the combination of the vertical distance 228 and thehorizontal distance 268. In one embodiment, for example, the further aparticular key structure 210 is from a center line or reference point,the further towards the edge the peak 222. This means that for thevector defining the distance between the peak 222 and center point 208of a given key structure, the magnitude of the vector increases thefurther that given key is from the centerline of the keyboard 100.

FIG. 4 is a simplified illustration of a keyboard implemented on amobile computing device, in accordance with an embodiment of theinvention. FIG. 4 illustrates a portion of a keyboard 300 correspondingto a cross-section provided by lines B-B for the key set of FIG. 1, withelements for operatively engaging the keyboard on a mobile computingdevice. For example, the keyboard 300 may be implemented on a mobilecomputing device similar to design and functionality such as shown inFIG. 5.

The keyboard 300 may include a plurality of key structures 310 (e.g.30-34) interconnected by a carrier 515 underneath a housing layer 355.Individual key structures 310 extend a height h from an outer surface356 the housing layer 355. An actuation member 320 may extend inwardfrom a bottom of each key structure 310. In one implementation, eachactuation member 320 may align with a corresponding electrical contactdome 330. The electrical contact domes 330 may be interconnected by asubstrate 335 or flex cable. Electrical leads and/or circuitry mayextend through the substrate 335 and interconnect to one or moreprocessors 350.

In an implementation shown by FIG. 4, each actuation member 320 may bejoined or integrally formed with each key structure 310. Alternatively,the actuation member 320 may be interconnected by glue or other meanswith the underside of the key structure 320. Still further, theactuation member 320 may connected to the contact domes 330. In eithercase, inward movement of the key structure 310 causes the correspondingactuation member 320 to actuate the aligned contact dome 330. Thecontact domes 330 may “snap” when pressed by the actuation members,corresponding to the individual contact dome collapsing onto an interiorcontact surface. This collapse causes a switch event, generating anelectrical signal that is directed to the processor 350.

In an embodiment, the key structures are each provided with a peak 322that is separated from the key structure center 312 by a distance thatincreases depending on how far the individual key structure is from acenterline of the keyboard. This separation and pitch variation providestactile separation for the user when operating the keyboard 300. Thecollapsibility of the contact dome 330 provides additional tactilefeedback.

Alternative Embodiments

While embodiments described with FIGS. 1-3 provide for key structureshaving symmetrical footprints, other embodiments may utilize keystructures having asymmetrical shaped keys. For example, a keyboard fora mobile computing device may include keys that are asymmetric about thehorizontal axis X and the vertical axis Y. Such key structures exist on,for example, the HANDSPRING TREO 600, manufactured by PALMONE, INC. Thedesign of offset peaks and/or pitch variations may be employed with suchkeyboards in a manner similar to embodiments shown above. If keystructures on the keyboard are uniformly shaped, then the spacingbetween adjacent keys at a common reference point (e.g. right edge ofeach key structure) will be less than the spacing of the peaks betweenthe same adjacent key structures.

It may also be possible for key structures on a keyboard to havedifferently shaped keys. For example, key structures on the boundary ofthe keyboard may be provided with a contoured edge to provide thekeyboard with a curved boundary. In such embodiments, the peaks ofindividual structures may be made offset with respect to a midpoint orcommon center point of some or all key structures, so that thepeak-to-peak distance between adjacent key structures is maximized.

While an embodiment described with FIG. 4 and elsewhere make referenceto key structures that are interconnected by carriers and/or molded as athickness having the peaks shown, other embodiments may include otherforms of key structures. For example, each key structure may correspondto a spring-loaded cap that is independently moveable on the surface ofthe housing. In such cases, the material used to form the caps (e.g.plastic) may be contoured to provide the desired spacing between thepeak and the center of a given key structure.

Mobile Computing Device

FIG. 5 is a top view of a mobile computing device on which an embodimentof the invention may be implemented. The mobile computing device 510 maycorrespond to a combination cell phone, organizer and text-messagingdevice (e.g. email). For text entry, the mobile computing device 510includes a small form-factor keyboard 510. The keyboard 510 includes aseparate key 520 for each alphabet character. Additional special keys(e.g. application launch, SHIFT, ENTER, ALT) may be included, so thatthe total number of keys is greater than 30. The keys are provided inrows and columns, so that a QWERTY style keyboard may be implemented.Other elements of the device 510 include a display 530, and an antenna540. The display presents content, including content generated by theuser manipulating the keys 520 of the device 510. The antenna 540 may bepart of a system that transmits and receives data over a cellularnetwork. The data may correspond to voice, text, image or other forms ofcommunications. The keys 520 may extend from a surface of a housing 550.

FIG. 5 shows the keys 520 uniformly spaced apart in an arced pattern (sothat individual rows form a smiley face). The keys may be individuallycontoured in a manner described with embodiments such as presented aboveto include offsetting peaks and/or pitch variations from key to key. AsFIG. 5 is a top view, the contours of the individual keys 520 are notshown. In an embodiment, the keys 520 are provided footprints that arevaried in shape to better accommodate the offsetting peaks and pitchvariation presented on the individual keys. In an embodiment such asshown, the footprint is substantially rectangular or square (withrounded corners) for keys that are centrally positioned in the keyboard.The further a key is positioned from a central column 555, the more skewthe shape of the footprint. Perimeter footprints may be most skewed,with each key 520 that is off center from central column 555 having atrapezoidal footprint.

Certain perimeter or edge keys 522, such as those forming corners, maybe provided a footprint that has an alternative shape. Thus, it ispossible for individual keys 520 in a given row to be irregular ascompared to other keys. Furthermore, the some or all keys in a given rowmay be asymmetrical. In the example provided by FIG. 5, keys 520centrally positioned have symmetrical footprints about both horizontaland vertical axes. The keys 520 that are skewed through positioningtowards the perimeter are symmetrical about just the vertical axis.Perimeter or edge keys 522 are asymmetrical. Even with variations insymmetry and footprint shape, peak variations and offsetting peaks maybe implemented on the individual keys 520 that form the keyboard orkeypad.

Alternative Embodiments

While an embodiment such as shown in FIG. 5 may include all keys in atleast three rows of the QWERTY layout to include peaks that formoffsets, alternative designs may be implemented. In one embodiment, onlya small portion of keys 520 in one or more given rows or columns has apeak that is offset from center. In such an embodiment, it is possiblefor the distance between the peaks of adjacent keys 520 may still beuniform, with additional spacing being provided by the narrowing of thespacing between the boundaries of individual keys.

In still another variation, an embodiment provides that variations inpeak position do not occur between each adjacent keys 520, but betweensome adjacent keys. The variation in the position of the peak betweenkeys of a given row/column may occur between, for example, every otherkey in a given row. In such an example, two adjacent keys may have peaksthat are offset from center, but still located in the same relativeposition on the individual key. In the same row/column, the next twoadjacent keys may have peaks that are offset in position with respect toone another.

CONCLUSION

Although illustrative embodiments of the invention have been describedin detail herein with reference to the accompanying drawings, it is tobe understood that the invention is not limited to those preciseembodiments. As such, many modifications and variations will be apparentto practitioners skilled in this art. Accordingly, it is intended thatthe scope of the invention be defined by the following claims and theirequivalents. Furthermore, it is contemplated that a particular featuredescribed either individually or as part of an embodiment can becombined with other individually described features, or parts of otherembodiments, even if the other features and embodiments make nomentioned of the particular feature. This, the absence of describingcombinations should not preclude the inventor from claiming rights tosuch combinations.

1. A keypad comprising: a plurality of key structures, whereinindividual key structures in the plurality of key structures aredistributed in a direction of at least a first axis; wherein each keystructure in the plurality of key structures includes an exteriorsurface for receiving user-contact, the exterior surface of each keystructure having a center reference and a peak, so that an offsetdistance between the center reference and the peak is greater than orequal to zero; and wherein the offset distance for at least two or morekey structures in the plurality of key structures is different based ona position of that key structure relative to a first reference line of asecond axis that is orthogonal to the first axis.
 2. The keypad of claim1, wherein a magnitude of the offset distance in the direction of thefirst axis ranges from (i) a minimum for one or more key structure inthe plurality of key structures that are closest to the first referenceline, to (ii) a maximum for one or more key structures in the pluralityof key structures that are furthest to the first reference line.
 3. Thekeypad of claim 2, wherein a peak-to-peak distance between the peaks ofkey structures that are adjacent in the direction of the first axis isabout equal for key structures in at least a majority of the pluralityof key structures.
 4. The keypad of claim 3, wherein a center referencedistance between the center references of key structures that areadjacent in the direction of the first axis is about equal for keystructures in at least a majority of the plurality of key structures. 5.The keypad of claim 1, further comprising a medium that interconnectseach of the plurality of key structures, and wherein each key structurein the plurality of key structures has a thickness corresponding to adimension that extends outward from the medium.
 6. The keypad of claim1, wherein the plurality of key structures are distributed in thedirection of the first axis and the second axis, and wherein the offsetdistance for at least two or more key structures in the plurality of keystructures is different based at least in part on a position of that keystructure relative to a second reference line of the first axis.
 7. Thekeypad of claim 6, wherein a magnitude of the offset distance in adirection of the second distance ranges from (i) a minimum for one ormore key structures in the plurality of key structures that are closestto the second reference line, to (ii) a maximum for one or more keystructures in the plurality of key structures that are furthest to thesecond reference line.
 8. The keypad of claim 7, wherein thepeak-to-peak distance between the peaks of key structures that areadjacent in the second direction is about the equal for key structuresin at least a majority of the plurality of key structures.
 9. The keypadof claim 8, wherein a center reference distance between the centerreferences of key structures that are adjacent in the direction of thesecond axis is about equal for key structures in at least the majorityof the plurality of key structures.
 10. The keypad of claim 1, whereinthe plurality of key structures form a QWERTY style keyboard.
 11. Thekeypad of claim 1, wherein a footprint of individual key structures inthe plurality of key structures is asymmetrical.
 12. A mobile computingdevice comprising: a housing; a keypad provided on a surface of thehousing, wherein the keypad includes a plurality of key structures;wherein each key structure in the plurality of key structures includesan exterior surface for receiving user-contact, the exterior surface ofeach key structure having a center reference and a peak, so that anoffset distance between the center reference and the peak is greaterthan or equal to zero; and wherein the offset distance for at least twoor more key structures in the plurality of key structures is differentbased on a position of that key structure relative to a first referenceline of a second axis that is orthogonal to the first axis.
 13. Themobile computing device of claim 12, wherein a magnitude of the offsetdistance in the direction of the first axis ranges from (i) a minimumfor one or more key structure in the plurality of key structures thatare closest to the first reference line, to (ii) a maximum for one ormore key structures in the plurality of key structures that are furthestto the first reference line.
 14. The mobile computing device of claim13, wherein a peak-to-peak distance between the peaks of key structuresthat are adjacent in the direction of the first axis is about equal forkey structures in at least a majority of the plurality of keystructures.
 15. The mobile computing device of claim 14, wherein acenter reference distance between the center references of keystructures that are adjacent in the direction of the first axis is aboutequal for key structures in at least a majority of the plurality of keystructures.
 16. The mobile computing device of claim 12, wherein theplurality of key structures are distributed in the direction of thefirst axis and the second axis, and wherein the offset distance for atleast two or more key structures in the plurality of key structures isdifferent based at least in part on a position of that key structurerelative to a second reference line of the first axis.
 17. The mobilecomputing device of claim 16, wherein a magnitude of the offset distancein a direction of the second distance ranges from (i) a minimum for oneor more key structures in the plurality of key structures that areclosest to the second reference line, to (ii) a maximum for one or morekey structures in the plurality of key structures that are furthest tothe second reference line.
 18. The mobile computing device of claim 7,wherein the peak-to-peak distance between the peaks of key structuresthat are adjacent in the second direction is about the equal for keystructures in at least a majority of the plurality of key structures.19. The mobile computing device of claim 18, wherein a center referencedistance between the center references of key structures that areadjacent in the direction of the second axis is about equal for keystructures in at least the majority of the plurality of key structures.20. A mobile computing device comprising: a housing; a keyboard providedon a surface of the housing, wherein the keyboard includes a pluralityof key structures; and a means for tactilely separating individual keyson the keyboard using a separation in a peak and a center reference ofthe individual keys.